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Author(s)

Elijah J. Petersen

Abstract

Determining the effects of various surface coatings on carbon nanotubes (CNTs) is critical given the numerous expected applications of CNTs and their inevitable release into ecosystems. To explore the potential ecotoxicological effects of CNT surface modifications, we modified multi-walled carbon nanotubes (MWNTs) with polyethyleneimine (PEI) coatings. Uptake and elimination experiments for PEI-MWNTs with various surface charges spiked to soils revealed limited earthworm accumulation and ready elimination. Conversely, Daphnia magna, an aquatic organism, accumulated substantial concentrations of PEI MWNTs and was only able to excrete them with algae feeding. This suggests that the availability of food in ecosystems will substantially affect the long-term fate of nanotubes ingested by daphnia. Quantification of the carbon nanotubes in earthworms and daphnia was performed using carbon-14 labeled nanotubes.